The invention concerns a sample changer for the automatic intake of a multitude of samples into the measurement position on the goniometer axis of an X-ray diffractometer--with an X-ray source for the creation of X-ray radiation--and a detector for the detection of the refracted X-ray beam from a sample in the measurement position in reflection mode. In the sample changer the individual samples--each showing a surface, which meets the goniometer axis at a tangent in the measurement position--are linearly arranged on an insertable magazine.
Such a particular sample changer is known from the manual "X-Ray Diffractometer D5000", Siemens AG, 1995, section 3.4.3 "Automatic 40 Sample Changer", pp. 3-21.
X-Ray diffractometers serve as a nondestructive analysis of material samples and are standard equipment in many of today's laboratories. According to the type of sample materials to be analyzed or the analytical question, this type of diffractometric measurement of a sample surface can be carried out in reflection mode or in transmission mode via the (thin) sample. In order to be able to measure a large number of samples on a routine basis--that is one right after the other without having to manually alter the equipment--most X-ray diffractometers comprise a device which automatically picks up and changes the actually measured samples.
In the publication "MX Labo Genius X-ray Diffractometer", MAC Science Co., Ltd., Yokohama, Japan, an automatic sample changer for an X-ray diffractometer with a rotatable magazine is described, which, however, is only suitable for use in reflection mode measurements.
Likewise a company brochure titled "X-ray Diffractometer Accessories", Scintag, Inc., Santa Clara, U.S.A. describes a rotatable magazine exclusively for reflection mode measurements. This company brochure describes an azimuth scanner--used for samples to be measured in transmission mode--which only accommodates a single sample and doesn't comprise any device that automatically picks up and changes the actual sample to be measured.
An automatic sample changer for an X-ray diffractometer based on a robot arm is offered by STOE & Cie GmbH, Darmstadt, Germany. This sample changer is suited only for transmission mode measurements and, due to the robot arm construction, is a quite expensive design.
The previously quoted manual concerning the X-ray Diffractometer "D 5000" manufactured by Siemens AG describes a linear magazine for the intake and automatic conveyance of flat sample frames--in slide format--into the X-ray diffractometer's measurement position. As a result, movement of the sample frames takes place perpendicular to the measurement plane. This well-known sample changer can, on the other hand, only be used for samples intended for reflection mode measurement, since the intake mechanism would be in the way of the beam transmitted through the sample when the detector, the sample and the source are essentially linearly arranged. Moreover, reflection mode measurements with grazing incidence are only possible with this known sample changer in cases where a sample rotation--as applied during powder measurements to improve measurement statistics--can be left out.
The purpose of this invention, in contrast, is to be able to modify a sample changer of the aforementioned type with the simplest mechanical means in such a way that it can be used in reflection mode as well as transmission mode measurements without having to redesign the system, and that it easily allows sample rotation in measurement position.